The Clinical Audiology Unit (CAU) of the NIDCD remains the sole clinical audiologic resource for intramural NIH. It continues as clinical research service an support for over 58 protocols, providing clinical research support for various branches, sections and units within most institutes. The CAU has 2 protocols with staff members as principal investigators and the chief, CAU, is now associate investigator/collaborator on 14 clinical research protocols (8 new studies were added in FY '92). Additionally, the CAU continues its longstanding relationship with the interinstitute Genetics Program, an its support of the ENT Clinical Service. This year the CAU has completed the first phase of data collection on Waardenburg subjects (NIDCD). The data analysis will begin shortly with emphasis on defining and evaluating auditory phenotypic characteristics of Waadenburg. The CAU has just begun the new NIDCD protocol on Nonsyndromic Hereditary Hearing impairment that includes the evaluation of auditory or audiovestibular function in families identified as having hereditary hearing loss with no other associated stigmata. Another new protocol, 'Auditory Fatigue,' generated within the CAU, although IRB approved, has not been activated due to lack of space. Renovations should be completed in Fall '92. CAU's collaborative work outside the NIDCD has also increased. Our work in the investigation of auditory system function in recessively inherited neurodegenerative metabolic disorders in children and young adults continues to be important. A specific audiologic finding in Type C Niemann-Pick has been determined to be particularly significant for both early diagnosis and estimates of severity and survival time. This work is being published collaboratively and is currently in press. The validity and significance of the 'Pikus Sign' in Niemann-Pick C was acknowledged in NIH Clinical Center Ground Rounds (May 1992_. CAU study of Type 2 Neurofibromatosis (NF2) in both affected an at risk individuals continues to be highly productive and has resulted in two publicaitons this fiscal year. We are currently active as collaborators on 5AIDS protocols and provide clinical service for 7 different AIDS studies from the NCI. In addition, this year the CAU completed study on auditory function in young adults with developmental disabilities in collaboration with NIMH, resulting in one publication and one article in press to date for this reporting period. Formal presentations and publications from several other studies are currently in various stages of analysis and preparation. We report that this fiscal year we provided detailed clinical follow-up growing numbers of patients at risk for ototoxic damage from 8 different studies from the NCI. The assessment of auditory function is achieved through precise study of puretone and speech sensitivity; suprathreshold studies of speech recognition; biomechanical measurement of middle ear function, and electrophysiologic study evoked potentials. Test strategies are developed for each disorder, including other specialized psychoacoustic or neurophysiologic studies as needed. There continues to be a dearth of audiologic literature in many diverse diseases and conditions. It is our purpose to provide new and pertinent information on the human auditory system in many of these conditions and thus improve human health an the quality of life . We now know that particular auditory system disfunctions may signal or reflect specific changes in other organ systems and thus it behooves us to understand the function of the auditory system and the relationship of abnormal auditory system function to other conditions. This unique approach to the study of hearing in the living human being is particularly relevant as it offers non-invasive study techniques coupled with speed, reliability and minimal expense.